perfectSquares.cpp

#include <vector>
using namespace std;
/*
Given an integer n, return the least number of perfect square numbers that sum to n.

A perfect square is an integer that is the square of an integer; in other words, it is the product of some integer with itself. For example, 1, 4, 9, and 16 are perfect squares while 3 and 11 are not.



Example 1:

Input: n = 12
Output: 3
Explanation: 12 = 4 + 4 + 4.
Example 2:

Input: n = 13
Output: 2
Explanation: 13 = 4 + 9.


Constraints:

1 <= n <= 104
""
*/
class Solution
{
public:
    int minNumbersToAdd(int target, const vector<int> &numbers)
    {
        vector<int> dp(target + 1, INT_MAX);
        dp[0] = 0;
        for (int i = 1; i <= target; i++)
        {
            for (int nr : numbers)
            {
                if (i >= nr && dp[i - nr] != INT_MAX)
                    dp[i] = min(dp[i], dp[i - nr] + 1);
            }
        }

        return dp[target];
    }
    int numSquares(int n)
    {
        vector<int> squares;
        for (int i = 1; i * i <= n; i++)
        {
            squares.push_back(i * i);
        }
        return minNumbersToAdd(n, squares);
    }
};